The study of past case studies to seek out lessons or meaning relevant to current or future cases is a common practice in academic research as well as in military planning. It is often referred to as research by analogue or analogy, and is a method used fairly regularly to study the potential for human systems to adapt to climate change (see M. Glantz 1988 Societal responses to regional climate change: Forecasting by analogy, Westview Press: Boulder). When it comes to predicting future human behaviour, unless one has a crystal ball there are not many methodological tools to choose from. One way is to attempt to create computerized models of human behaviour, such as agent-based modeling. Another is to undertake exercises that generate future scenarios, typically done by organizing a group of 'experts' (i.e. people with specialized knowledge of the problem at hand) and providing them with a framework and set of tools, parameters and instructions to use. And then there is research by analogue. None is perfect; each of these methods has its inherent flaws.
In my own research into the effects of climate change on human migration patterns, I have on several occasions used the 1930s droughts on the North American Great Plains as an analogue for studying how rural populations adapt to drought generally, and to tease out lessons about how future climate change-related droughts may affect the well-being of rural populations and affect human population patterns. It's not a perfect analogue for the present day. In the 1930s, more North Americans lived in rural areas or small communities than in big cities; today it's the opposite. Agricultural production represents a small portion of the overall Canadian and US economies today; back in the 1930s small family farms provided many of the jobs and sources of income in North America. the way we farm has changed considerably; today, large corporate-owned factory farms using intensive methods, chemicals, irrigation, etc increasingly dominate the land. And, interestingly enough, the long severe droughts of the 1930s that dessicated much of the Great Plains, drove hundreds of thousands from their homes and led to people calling it the region the 'Dust Bowl' actually weren't all that severe in comparison with previous droughts that occurred before European farmers came to the West nor in comparison with the type of droughts the West has experienced in the past decade and is likely to continue to experience in coming decades (see the research of Dave Sauchyn at University of Regina for long-term drought records reconstructed from tree rings)) .
So why use the 1930s as an analogue? For starters, it is arguably the worst environmental disaster in North American history, and coincided with the worst economic crisis in living memory, the Great Depression. The combination of economic and environmental hardship threw North American society and the global economy into crisis, and led to a sea change in American politics: Americans abandoned Hoover's laissez-faire market capitalist economy for Roosevelt's interventionist New Deal policies, which permanent change the relationship between the federal government and the citizen. When reviewing the predictions for future climatic conditions due to anthropogenic climate change, it is hard to imagine any scenario where severe environmental changes would not be accompanied be severe economic crisis and necessitate dramatic changes in political, economic and social policies.
In other words, many of the specific details of day-to-day life and of North American socio-economic structures and institutions have changed since the 1930s, but the potential impacts of climate change on human systems will be of a scale we have not seen since the 1930s, so it's worth remembering how our society adapted last time around. When you talk to people who lived through the 1930s (and there are still a fair number of them alive today) you are talking to experts in adaptation to environmental stress. While the specific adaptations they and their families chose to make in the 1930s may not be the types we would use today, the process of choosing courses of action during conditions of environmental stress, the recognition of places where governments could have intervened to reduce the damage to livelihoods and well-being, and the types of actions that need to be taken now to avoid crisis conditions in the first place: these are things those who lived through the 1930s can guide us with.
Which brings me back to the question of whether Canada's military can learn from the Soviet Union's experience in Afghanistan in the 1980s. I suspect there is relatively little of significant value, simply because the similarities between the two cases are systematically and fundamentally different. The Soviet Union's invasion and occupation of Afghanistan was an overt act of expansionist aggression, the idea of which had its origins the early part of the 20th century, when Britain and Russia were engaged in 'The Great Game' of colonialist expansion (see P. Hopkirk 1994. The Great Game, Kodansha Press: New York). Soviet soldiers were despised by the local population, regardless of ethnic group, and rightly so. The Soviet military indiscriminately attacked civilians, looted and vandalized homes and property, and committed any number of acts which we would today label as war crimes. A gripping account of life inside Soviet-occupied Afghanistan can be found in Danziger's Travels (Grafton Books, London: 1987), in which the author travels across the country by land in the company of mujahedin fighters. the chapters on Afghanistan in Robert Fisk's The Great War for Civilisation are also worth a read, although Fisk was never able to 'embed' himself with local fighters the way Nick Danziger did.
Canadian forces are not in Afghanistan for the same reasons as were the Soviets, nor do they conduct themselves in anywhere near the same fashion. Their goal is to provide the security necessary to construct a civil society in which basic human rights are respected and in which basic human needs are met. The Taleban regime which was removed from power 6+ years ago was a despicable regime which the majority of Afghans by all accounts do not miss. Yes, military geographers could likely learn by studying the Soviet experience where mujahedin groups were more likely to launch attacks against Soviet forces, and might gain a few nuggets of information about well-travelled smuggling routes and such things.
Overall, however, I suspect there would be few great lessons to be taken from the Soviet occupation except the obvious one that blatant aggression and the use of military force against civilians are necessarily evil and will rightly stimulate hostility and widespread counter-violence from the population against which such acts are perpetrated. While it is always good practice to leave no stone unturned, and therefore to indeed dedicate some resources to studying the history of Soviet aggression in Afghanistan, I doubt there would be much to learn that would have helped reduce Canadian casualties to date or hasten the end of the mission.